How to get permission to export passport abroad?

Hi, My Irish passport was issued and delivered to my address in London. It arrived a few days after I left the UK for a few months. My cousin collected it for me and I would like to ship it by courier to either Thailand or Bali (Indonesia). I've read that to export passports, I need to get permission from the UK Customs. I can't find any information about this on the HMRC site or online – how do I get this permission? Will I get a letter or just logged on their system that I'm sending it so it doesn't get stopped at customs? Any information is appreciated.

Hi Brandon Josi,
I would advise contacting the Customs and International trade helpline on 0300 322 9434 if you have any other issues with your query.
Thank you.